Geminids

I need this to do a continuing assessment of ISS passes over the UK that are "lit" by GRAVES. I was considering an exercise to do every month and look at what passes there had been and then checking my radio data. I am not sure what would be the best approach; either scanning through hundreds of spectrum lab images, developing a conditional action script in Spectrum Lab to detect with reasonable confidence, ISS scatter. But I will help to know when and where to look - and I.S.S Tracker gave this 😕 Or maybe there is a way to set up a ISS predictor app that would list upcoming passes over the Channel and UK that would do the job?` Or I could look back at records going back to 2016. So, in answer to your question, I think that whatever way I do it I would need, say, at lest three months worth of history perhaps. Ideally ground lat and location.

In the past I have used the ISS Tacker web browser app to provide historical data of the satellite latitude and longitude for past dates and times, but it seems to be broken now 😞 - any pointers on an alternative would be very welcome.

Hallo Stormchaser on Stornoway Don't know why I hadn't seen your posting of June 28th before - but now I have 🙂 This is a really interesting study you are doing particularly in mapping out the regions of the sky that return scattering from GRAVES. It adds to the Narvarro paper that wxsatuser referred me to in a recent posting in another thread. Those rear/side lobes are mainly unknown and the fact that they are from a reflection from the ground with local buildings giving clutter makes them even more difficult (impossible?) to predict. If you have any more evidence of ISS or other satellites I would be most interested. Also, what do you use for satellite location reporting?

In the north, near Manchester, i use 3 element Yagis with head amp and seldom get tropo but almost invariably i get moon bounce. Really i would like to know the lat and longitude go ISS when detected to find the furthest north it can be "seen", to help with a meteor simulation model i have developed.

Yes, wxsatuser, that is what I half remembered. The link to Navarro's paper from Czechoslovakia has their measurements. Could we do a similar thing in the UK and extend the "sky print" ? No idea how to go about it myself but I am willing to try.

I have seen there are many posts of ISS detection using rdaio scatter from the GRAVES transmitter. Is it possible to detect the ISS from the side or rear lobes, in the UK? If so it would nice to plot out where the ISS is and backtrack to GRAVES and map out these side lobes. I think that this has been done by other European countries and I would like to know what are the regions of space where meteors scatter.

I am interested if anyone has downloaded this software and are putting it into use. It can generate a lot of data and would am keen to discuss ways of using it for scientific study etc.

I am away at the moment and am interested to know if there was any of the predicted Draconids activity.

I have been trialing a new meteor data logger and analyser that is written by Wolfgang Kaufmann. It has been around for a couple of years and I have now just got round to trying out properly. I wish I had checked this out a lot earlier - now I think we can do some serious analysis of radio meteor and perhaps do some science! There are two Python applications: one logs the data and the other processes it. The apps can be found at http://www.ars-electromagnetica.de/robs/download.html and there are links to his IMO paper which describes it. The big thing here is that the program logs track all meteor tracks - specular, long duratoion and head echoes . For my tests I ran a FCDP+ with HDSDR and used a VAC to connect to Specrtum Lab using the set up I usually use for routine logging and also to the Python Logger. I ran it for about 20 days in September - a non-shower period. The csv file produced was over 25Mbytes. This is loaded into the Process Data App where cleaning and conflation (joining seperataed parts of a track broken by GRAVES switching) is first done. The App has a number of functions that analyses the data. Underdernse , overdense, long duration, distributions, hourly counts RMOB output are all catered for. The head echo frequency slope is a particlualrly interesting plot and is employed in WGN 46:6 (2018) pp 201 -204 in an investigation of sporadic meteor radiants and dynamics. Below is a first look at my own data and I can see a bit of study is going to be requirefd 🙂 The Process Data App can also generate a number of csv files for overdense data, under dense head echoes etc. I give a selection of plots I have made from these data in the pdf below Meteor Logger Output.pdf The pdf shows the detail of the Meteor Logger data and compares it with Spectrum Lab specrotgrammes . The programs do require the Python interpretor to be running and there is a learning curve to go up (I am only just started) and there are significant amounts of data that can be used in analysis. I will be moving this program into routine use and start looking at the data as I have never been able to before 🙂 I think it is well woth the efoort for the serious radio meteor observer.

You are making good progress. Keep in touch here.

I have results for all July and August to date. I will look at your results and compare. It does raise the point- what is the bet way to display hourly count rates? Lines, bars (I favour), tables, colourgrammes (also useful to show diurnal changes and progression during month) Also are your counts manual or automated in some way? Are the blanks in your table where you were not monitoring or there was nothing to count?

I am away on holiday in a few days and will give you some brief details of the software. For all of my data manipulation, ie reading the Spectrum Lab (SL) logs, filtering, distributions, and plots I use Wavemetrics' Igor Pro which is a plotting and analysis application with a powerful programming capability. I have written routines using Igor Pro to do all of the tasks automatically. The top plot above is done with this - plotting is very flexible. As you can see I do get a significant ammount of Moon Bounce events in my data; this may be because I use masthead pre-amps on my systems. (Incidentally a snapshot of part of the RF circuit is shown on my Icon). To filter this out I use the programme EMEPlanner to provide Moon Doppler shift at 10 minute intervals for the month. I copy and paste the data from EMEPlanner into Excel and run a VBA macro to format it. It is then imported into Igor Pro. When I have loaded some of my SL data log into Igor Pro I run my filter macro, which checks each event in the log for certain criteria. The Moon part of the filter compares the time and frequency of the particular log entry with the interpolates Moon Doppler shift data and, if the frequency of event matches within limits, it is filtered out. In the example above the 4300 Moon events are filtered from total log of around 37000 events in a second or two. The technique does require accurate time and frequency which I achieve. It seems to work quite well and I intend to compare the patterns of my antennas with these Moon data. The Colourgrammes are done in Excel because it is easier to use the cells to construct it. And, as you might have guessed, the counting is done in Igor Pro, exported and then imported to Excel where a VBA macro takes the data and makes the plots shown above.

Well, I guess you could leave the Moon bounce data in .... Just deleted wrong stream attributions. Any thoughts on what the activity is?

If you pick up interference and moon bounce as I do, there could be trouble with getting a true count of meteor actvity if you do it in Spectrum Lab - unless, that is you can do this clean up in SL.

I think the relatively low frequency of the TX (55MHz) explains a lot to me about the nature of you spectrograms. Nevertheless, nice captures.

I Agree with John, nice shots. I note you are in the US. Could you please let us know some details of the Transmitter and software you are using for the nice spectrograms.

There is a design on the BAA Radio Astronomy Group site (unfortuntaely not actively maintained at the moment but still open) that I have built and works well. It is designed specifically for GRAVES and a number of other people in that group use it. It featured in a Sky at Night Article (BBC mag) http://www.britastro.org/radio/downloads/SkyAtNight/BBC_SatN_HOWTOOBSERVEMETEORS.pdf There are other interetsing radio meteor articles on their pages still.

I note from your website that you are a keen Astro Photographer. Are you as familiar with Radio Meteors? I note you take the csv files from Spectrum Lab into an excel spread sheet. The solution to hourly contain will probably involve some programming. I use another app to do the counting using its internal programmining language and import it to Excel for what is commonly called a colourgramme plot of days against hours with the colour of the cells indicating the count. For Excel programming the count routines can be achieved in Visual Basic which is quite a powerful language. Are you familiar with VB?

I see two very faint traces on one of my antennas (Blue channel) pointing to GRAVES with H-pol. Sorry, can't help with ID

As a start I have asked the antenna designer if he can give me detailed radition patterns, naturally he is reluctant to share his commercial design models. I also, over a number of years been interested in the moon bounce signals and can extract them digitally from the rest of the events. I am confident I have the Lunar position and Doppler at given time that correlate with my recordings. At the moment this is part of the general filtering of non-meteor data but it will bear further analysis when i get the time. The plots below show real (meteor) event frequencies in a month period in blue and Moon bounce as downward red lines. Horizontal lines in red are interference lines. As can be seen the detection of th moon bounce signal is different between the three antennas. Signal strength of Moon bounce will also be analysed. I think that a slow speed Doppler shift >may< depend on the trajectory: for example a very shallow angle would allow a long time in the ionosphere and coupled with an appropriate direction over land .... as I said I will try some numbers ... No the majority of my head echoes are much shorter. (I am still working on head echo capture techniques) Actually looking at my own spectrorams in more detail, I must agree with the spikes being Spectrum Lab's FFT artefacts rather than the other type of long duration event that I get where there appear to be a range of frequencies of similar signal strength. Yes. Thanks for the thought provoking discussion. Mike

The antenna array, Richard, was intended for the very purpose of measuring more parameters. One of the thins I do is keep my eye out for reported video meteors with trajectory data that coincide with my radio observations. The system is still in development and I have much more to learn about it - and then to interpret meteor results. I have yet to do a top to bottom calibration of the channels. The head echo and subsequent long, spectrally wide trail is typical of meteors. Having thought about it overnight, by the same reasoning that , in the higher UK latitudes GRAVES meteor scatter cannot be observed because it is below the radio horizon, if the "junk" was entering south of Dijon, the subsequent E-layer ionization would also be below the horizon. The fact that there are seasonal variations in E-layer ionization which is enhanced by the passage of meteors could lead to an interesting study of any annual differences in maximum signal levels on a statistical basis (distributions such as in my earlier post perhaps). There was a paper recently on "Solar cycle variation in radio meteor rates" , by MJ Campbell-Brown, MNRAS 000, 10 (2019) in a similar vein. As for the relative strength and proximity to me, again I have been thinking about this and remembered some rough calculations I did using the radar equation and a "standard" radar cross target and fixed height so that just the slant ranges from Dijon to object and object to me were the only variables. This yield a variation in signal level, the highest being over Dijon and me and the dip of -7dB in the middle. I will try to think about the variations in "angular" velocity and trajectory to see how that changes the frequency slope. Mike

Thanks for the negative report Richard - I hope your system is back on line soon. I take your point about the slow head echo - a quick measurement of the spectrogram gives a duration for the visible part on the bottom plot of just over two seconds and 255 Hz shift (124Hz/s slope), and as you say, it is not easy to get velocity from this, particularly because the location of the object is unkown. I must admit I haven't considered space junk before. Like you, the geometry is not right here to get meteor scatter from anything other than the GRAVES rear/side lobes. But of course if it's higher altitude it could be junk. Are any studies conducted into such debris detection and has anyone here and are there any confirmed recordings? How can junk and meteor events be differentiated? Would one have expected space junk to spin and hence generated glint? I have three antennas: one points towards Dijon as shown below. The idea of the vertically pointing Red and Green channels is to provide better sky coverage than traditional orientation. It is a pity you were off-line at the time because a comparative record would have been interesting and might have confirmed or otherwise your suggestions . ... but there may be other observers out there who did capture something? Mike PS New here - does the Notify me of replies work? Also sorry about the image size - is there a way to make them smaller.

To put the SNR in context here is the distribution of counts in given 1dB S NR bins for the three systems so far this month. The higher the SNR the stronger the echo. The SNRs represent one event in over 10000 so far this month.

I would be interested to know if anyone captured the very strong echo I received on my systems on on June 14th at 20:43:40 UT. I think these are possibly the strongest I have ever recorded with SNRs of 78, 69 and 81 respectively. It may well have been quite local to me in Hayfield, Derbyshire. Mike

Good results! It is an interesting period with a number of overlapping daytime showers. My results show peaks on different days depending on which of the (3) antennas I am using and where they are pointing.